Inhibitory control is frequently impaired following pediatric traumatic brain injury (TBI), and deficits in inhibitory control impact a child's function in school and at home and ultimately their likelihood for successful community integration as an adult. The long-term goal is to understand the neural mechanisms underlying the recovery of inhibitory control, including that involved in self-control of emotional expression and in social situations, in order to identify children at high risk for ongoing problems in these domains and to evaluate the efficacy of interventions designed to optimize inhibitory control. The focus of this proposal is to understand the recovery of inhibitory control over 18 months following pediatric TBI using laboratory assessments and parent-report measures of behavior in the home and community and to identify neuroimaging predictors and correlates of chronic inhibitory control. The specific aims are to 1) describe the pattern of recovery of varying aspects of inhibitory control over 18 months following moderate to severe pediatric TBI, 2) identify imaging measures which, after moderate to severe TBI in childhood, a) correlate with current inhibitory control, b) predict inhibitory control at one year following injury, and c) predict future imaging findings, and 3) identify, in children with moderate to severe TBI, changes in imaging measures between 2 months and 1 year following injury which are associated with improved inhibitory control over the same time period. Neuroimaging methods will include diffusion tensor imaging (DTI), magnetic resonance spectroscopic imaging (MRSI), and morphometric analyses, with primary analyses consisting of the relationship of frontal lobe integrity with measures of inhibitory control. This project is proposed as part of a career development plan for the PI, a pediatric rehabilitation physician, to obtain training in longitudinal study design and data analysis, neurobehavioral evaluation after pediatric TBI including assessment of inhibitory control and social function, and processing and analysis of DTI, MRSI, and structural imaging data from children with TBI. The Kennedy Krieger Institute and Johns Hopkins University provide an exceptional environment to enable the PI to become an independent investigator studying brain-behavior relationships after pediatric TBI. Public Health Relevance: After brain injury, many children have difficulty with controlling their behavior, which leads to problems in school and at home. The goal of this study is to develop ways to better understand which children are at risk to have this problem long-term after brain injury. This information will help children receive treatment to optimize their behavior as soon as possible and will allow studies of the efficacy of these treatments.